1 Introduction and Roadmap

This section includes information on how and why to use this guide and high availability environments. This section includes the following topics:

Section 1.1, "How to Use This Guide."
Section 1.2, "Setting up a Highly Available Environment"
Section 1.3, "New and Changed Features in This Release"
Section 1.4, "What is High Availability?"
Section 1.5, "High Availability Solutions"
Section 1.6, "Understanding the Oracle Fusion Middleware Standard HA Topology"

1.1 How to Use This Guide

Use this document as a reference guide for information on high availability concepts and tasks as you set up a highly available environment.

Before you use this guide, you must have a standard installation topology set up for your product. This is the required starting point for setting up high availability. See the topics "Understanding the Oracle Fusion Middleware Infrastructure Standard Installation Topology" and "Roadmap for Installing and Configuring the Standard Installation Topology" to set up the standard installation topology.

1.2 Setting up a Highly Available Environment

The following table describes tasks to set up a highly available environment and resources for information that is not in this guide.

Table 1-1 Setting up a Highly Available Environment

Task	Description	For more information
Performing administrative tasks and preparing your environment	Common tasks to perform on a newly-created domain.	See "Administering and Preparing your WebLogic Domain for High Availability" in your product installation guide.
Planning your WebLogic Server Installation	Covers understanding your topology and determining the distribution, components, and features you need.	See Planning an Installation of Oracle Fusion Middleware
Installing the WebLogic Server Software	Describes how to start the installation process and go through installation screens.	See the topic "Installing the Oracle Fusion Middleware Infrastructure Software" in your product installation guide.
Configuring a domain	Creating and configuring a domain	See "Configuring your Oracle Fusion Middleware Infrastructure Domain" in your product installation guide.
Managing Oracle Fusion Middleware	Includes how to: start and stop, change ports, deploy applications, and back up and recover Oracle Fusion Middleware.	See Oracle Fusion Middleware Administrator's Guide
Monitoring and optimizing performance in the Oracle Fusion Middleware environment.	For components that affect performance, use multiple components for optimal performance, and design applications for performance.	See Oracle Fusion Middleware Tuning Performance Guide
Setting up a product-specific enterprise deployment	Oracle best practices blueprints based on proven Oracle high availability and security technologies and recommendations for a product-specific enterprise deployment.	See your product's Enterprise Deployment Guide
Administering the product environment	To deploy, manage, monitor, and configure applications using the product.	See your product's Administrator's Guide
Configuring Node Manager	Use Node Manager to start, shut down, and restart the Administration Server and Managed Servers from a remote location. It is an essential tool for a high availability environment.	See Administering Node Manager for Oracle WebLogic Server

1.3 New and Changed Features in This Release

Oracle Fusion Middleware 12c (12.2.1.0.0) includes the following new and changed concepts and features:

Support for WebCenter. See Chapter 10, "Configuring High Availability for Oracle WebCenter Components."
Support for BI. See Section 11.3, "Deploying BI."

1.4 What is High Availability?

High availability is the ability of a system or device to be available when it is needed.

A high availability architecture ensures that users can access a system without loss of service. Deploying a high availability system minimizes the time when the system is down, or unavailable, and maximizes the time when it is running, or available.

High availability comes from redundant systems and components. You can categorize high availability solutions by their level of redundancy into active-active solutions and active-passive solutions.

See the following topics:

Section 1.4.1, "Active-Active High Availability Solutions"
Section 1.4.2, "Active-Passive High Availability Solutions"

1.4.1 Active-Active High Availability Solutions

An active-active solution deploys two or more active servers to improve scalability and provide high availability. In active-active deployments, all instances handle requests concurrently. Oracle recommends active-active solutions for all single-site middleware deployments.

1.4.2 Active-Passive High Availability Solutions

An active-passive solution deploys one active instance that handles requests and one passive instance that is on standby. If the active node fails, the standby node activates and the middle-tier components continue servicing clients from that node. All middle-tier components fail over to the new active node. No middle-tier components run on a failed node after failover. Oracle supports active-passive deployments for all components.

1.5 High Availability Solutions

You can categorize high availability solutions into local high availability solutions that provide high availability in a single data center deployment, and disaster recovery solutions.

Local high availability solutions can protect against process, node, and media failures, as well as human errors, ensuring availability in a single data center deployment.

Disaster recovery solutions are usually geographically distributed deployments that protect your applications from disasters such as floods or regional network outages. You can protect against physical disasters that affect an entire data center by deploying geographically-distributed disaster recovery solutions. For more on disaster recovery for Oracle Fusion Middleware components, see Oracle Fusion Middleware Disaster Recovery Guide

1.6 Understanding the Oracle Fusion Middleware Standard HA Topology

The following figure shows the recommended standard high availability topology for a local, highly available Oracle Fusion Middleware deployment.

This deployment is consistent with the infrastructure standard installation topology and Oracle HTTP Server standard installation topology if you followed steps in Oracle Fusion Middleware Installing and Configuring the Oracle Fusion Middleware Infrastructure and Oracle Fusion Middleware Installing and Configuring Oracle HTTP Server.

Figure 1-1 Oracle Fusion Middleware Highly Available Deployment Topology (Typical Enterprise)

Description of "Figure 1-1 Oracle Fusion Middleware Highly Available Deployment Topology (Typical Enterprise)"

This topology shows a multi-tiered architecture. Users access the system from the client tier. Requests go through a hardware load balancer, which routes them to Web servers running Oracle HTTP Servers in the web tier. Web servers use Proxy Plug-in (mod_wl_ohs) to route requests to the WebLogic cluster in the application tier. Applications running on the WebLogic cluster in the application tier then interact with the database cluster in the data tier to service the request.

The following table describes elements in the preceding figure.

Table 1-2 Description of the Elements in the Oracle Fusion Middleware Infrastructure Standard High Availability Topology

Element	Description and Links to Additional Documentation
APPHOST	Machine that hosts the application tier.
WEBHOST	Machine that hosts the web tier.
WebLogic Domain	A logically related group of Java components, in this case, the Administration Server, Managed Servers, and other software components. For more information, see "What is an Oracle WebLogic Server Domain?" in Understanding Oracle Fusion Middleware.
Administration Server	Central control entity of a domain. Maintains a domain's configuration objects and distributes configuration changes to Managed Servers.
Enterprise Manager	Oracle Enterprise Manager Fusion Middleware Control. The main tool that you use to manage a domain.
Cluster	A collection of multiple WebLogic Server instances running simultaneously and working together.
Machine	Logical representation of the computer that hosts one or more WebLogic Server instances (servers). Machines are the logical 'glue' between Managed Servers and Node Manager; to start or stop a Managed Server with Node Manager, the Managed Server must be associated with a machine.
Managed Server	Host for applications, application components, Web services, and their associated resources. See "Oracle Enterprise Manager Fusion Middleware Control" in Understanding Oracle Fusion Middleware.
Infrastructure	Collection of services that includes: Metadata repository (MDS). Contains metadata for components, such as Oracle Application Developer Framework. See "What is the Metadata Repository?" in Understanding Oracle Fusion Middleware. Oracle Application Developer Framework (Oracle ADF) Oracle Web Services Manager (OWSM)